1. Field of the Invention
The invention relates to a method and to equipment for producing or obtaining glucose from a starch solution.
2. Description of the Related Art
The conversion of starch from a starch solution into glucose or various sugars is an important sector of the starch processing industry and at the same time one of the economically most significant fields of application in food technology. The most important vegetable suppliers of starch for this purpose are maize, potatoes and wheat.
The process of obtaining glucose or dextrose proceeds in various stages. In a first stage a defined starch suspension is generally produced from a previously produced aqueous starch solution and additional water. The starch suspension is liquefied by the addition of water vapour, enzymes and/or acid. A mixture of maltoses (barley sugar) and dextrines (an intermediate form of starch and dextrose) is produced therefrom by means of acid or enzymatic hydrolysis. The starch solution is saccharified by adding additional enzymes and/or acids. During starch saccharification the resultant decomposition products are decomposed further to form simple sugars (monosaccharides). A saccharified crude syrup which is a mixture of glucose (grape sugar) and fructose (fruit sugar) forms. However, the crude syrup also contains important protein and fat contents and substantially unsaccharified constituents which have to be filtered out to produce a finished dextrose product from the saccharified crude syrup.
Filtration is carried out in multi-stage ultrafiltration units or vacuum rotary filters with translucent silica glass (Kieselguhr) as the filtering medium and the undesired by-products, such as fat and protein, are thus separated.
Process steps on an ion exchanger, final cleaning and concentration then follow until finally the desired glucose or dextrose products can be produced in the end state by mixing various qualities of dextrose.
In the above process sequence problems occur in particular during said filtration of the saccharified crude syrup, which problems are reflected in a rapid drop in the power of the filters used, a short service life of these filters, instable process management and high cleaning expenditure and high consumption of filtering auxiliaries.
In the process of obtaining glucose or dextrose it should also be noted that sugar losses are to be avoided as far as possible, and therefore the undesirable by-products, such as fats and protein, have to be removed as far as possible without a simultaneous discharge of sugar. Very high demands are therefore made on the multi-stage ultrafiltration units and vacuum rotary filters used.